This invention relates to a novel composition containing urea and select trace elements for treating, protecting and re-epitheliazation of cutaneous wounds and damaged skin.
Urea has been long recognized as a cosmetic ingredient in formulations acting as a humectant and moisturizer. Urea is also recognized as a medically useful keratolytic agent because of urea""s ability at high concentrations to solubilize and denature protein. High concentrations of urea are also known to have an antibacterial effect.
U.S. Pat. No. 5,919,470 describes dermatological compositions using high concentrations of urea for treating xerosis and other skin conditions. This patent is being incorporated herein by reference.
Urea is known to have a strong proteolytic action and is an effective keratolytic agent particularly at an optimal concentration of 40%. Urea is very effective in dispersing epidermal keratin. Urea is non-toxic even at these high concentrations.
Trace elements play an important role in the biochemistry of living organisms including wound healing and healthy skin. Removal of necrotic tissue from wounds is essential to facilitate wound healing. Eschar and devitalized tissue may be removed by sharp, autolytic, enzymatic or surgical debridement. Urea is an excellent chemical debridement agent and can be applied directly to the wound became it is non-toxic.
Wound healing is promoted through maintenance of a moist environment and an environment which prevents microbial contamination. Both these essential wound healing aspects are provided by urea, as urea has good antimicrobial properties and can entrap water in the wound tissue/skin. Besides urea is an excellent chemical debridement agent particularly for eschar and devitalized skin and nail.
Trace amounts of zinc, copper and manganese are known to help in accelerating the healing of cutaneous wounds. Although the mechanism by which this is achieved is not clearly understood, these trace elements accelerate the re-epitheliazation of cutaneous wounds. Zinc, copper and manganese promote keratoinocyte proliferation.
There remains a need in the industry to improve upon compositions used in wound healing and repairing damaged skin.
We have found that combining urea and trace amounts of zinc, copper and manganese in a dermatological composition provides a novel approach for treating, protecting and re-epitheliazation of cutaneous wounds and the skin.
Accordingly, the present invention includes an improved method of treatment of a variety of dermatoses characterized by dry scaly skin, and cutaneous wounds using concentrations of about 21 to about 40 wt-% of urea in a suitably defined formulation containing trace elements of zinc, copper and manganese.
Thus, one aspect of the present invention is a dermatological composition including from about 21 to about 40 wt-% urea and trace elements of zinc, copper and manganese and the balance being dermatologically acceptable excipients.
The use of such high concentrations of urea combined with skin protectants of an oleaginous nature derived from petroleum and further combined with suitable emulsifiers and thickeners have been found to be effective for treating dermatological conditions manifested by dry scaly skin and cutaneous wounds without the need of traditional preservatives.
Accordingly, another aspect of the present invention is a dermatological composition including:
a) about 21 to about 40 wt-% urea;
b) trace amounts of zinc (1 ppm to 0.2%)
c) trace amounts of copper (1 ppm to 0.2%)
d) trace amounts of manganese (1 ppm to 0.2%)
e) about 5.5 to about 20 wt-% petrolatum or a synthetic or semi-synthetic hydrocarbon, or a semi-solid mixture thereof;
f) about 10 to about 20 wt-% of a liquid petrolatum or a synthetic or semi-synthetic oleaginous liquid fraction, or a mixture thereof;
g) about 0.25 to about 2 wt-% of C16-18 aliphatic straight or branched chain fatty alcohol or fatty acid, or a mixture thereof;
h) about 1 to about 5 wt-% propylene glycol;
i) about 1 to about 3 wt-% glyceryl stearate;
j) about 0.01 to about 0.5 wt-% xanthum gum; and
k) the balance being water.
Still another embodiment of the invention includes a dermatological composition containing:
a) about 21 to about 40 wt-% urea;
b) trace amounts of zinc (1 ppm to 0.2%)
c) trace amounts of copper (1 ppm to 0.2%)
d) trace amounts of manganese (1 ppm to 0.2%)
e) about 5.5 to about 20 wt-% petrolatum or a synthetic or semi-synthetic hydrocarbon, or a semi-solid mixture thereof;
f) about 10 to about 20 wt-% of a liquid petrolatum or a synthetic or semi-synthetic oleaginous liquid fraction, or a mixture thereof;
g) about 0.25 to about 2 wt-% of a C16-18 aliphatic straight or branched chain fatty alcohol or fatty acid, or a mixture thereof;
h) about 1 to about 5 wt-% propylene glycol;
i) about 1 to about 2 wt-% glyceryl stearate;
j) about 0.01 to about 0.5 wt-% xanthan gum;
k) about 0.05 to about 30 wt-% of a mixture of a carbomer and triethanolamine; and the balance being water.
Still another aspect of the present invention is a method of treating skin and cutaneous wounds by applying to an affected area in need of treatment an effective amount of a semi-solid dermatological composition containing about 21 to about 40 wt-% urea and trace amounts of zinc, copper and manganese as their respective pharmaceutically acceptable, i.e., bio-compatible salts.